As Walmart announced plans today to label certain foods with a new green "Great for You" label, some diet and nutrition experts told ABC News they applauded the move, while others questioned whether a company that sells food could set objective standards for what is healthy.

Dr. Darwin Deen, a family doctor and nutrition educator, told ABC News that "an independent opinion of a food's healthfulness is a good idea but as always, the devil is in the details."

Walmart, the largest food retailer in United States, will put the new label on select products that meet defined criteria.in its Great Value and Marketside lines. Customers will begin to see the new label on products starting in the spring.

The company said the "Great for You" products meet the rigorous nutrition criteria established by the U.S. Food and Drug Administration, the U.S. Department of Agriculture and the Institute of Medicine.

"Moms are telling us they want to make healthier choices for their families but need help deciphering all the claims and information already displayed on products," said Andrea Thomas, senior vice president of sustainability at Walmart.

Walmart's New Label on Front of Packaging

One difference that sets Walmart's labeling system apart from other nutrition labeling systems, such as NuVal scores, is that the label is on the front of the product rather than on store shelves.

Customers won't have to remember what "healthy" products they purchased because they can see what they are when they look in their cupboards at home.

Walmart's new labels will go on fruits and vegetables, as well as whole grains, high-fiber, low-fat dairy products, seeds, nuts and lean meats. The label limits the amount of total saturated and trans fats, added sugars and sodium levels a product can contain.

"I believe that Walmart's initiative, in principle, is an excellent one, provided that the labeling is based on sound nutritional evidence," said Pascal Imperato, dean of the School of Public Health at SUNY Downstate Medical Center in New York. "A stamp of approval as 'healthy' could mislead if it is not linked to label information about vitamin and mineral content, fat and sugar levels, chemical additives ... all of which are of importance to sound and healthy nutrition."

"People already have the information they need on the food label," said Lona Sandon, an assistant professor of clinical nutrition at University of Texas Southwestern and a spokeswoman for the Academy of Nutrition and Dietetics. "Just turn the box around and take a look at the Nutrition Facts Panel. You do not need a special rating system to tell you that fruits, vegetables, whole grains and lean meats are good for you."

But Walmart believes its "Great for You" label will make it easier for customers to find these healthy gems.

"Walmart's effort to bring healthier food to kitchen tables nationwide was inspired by our customers and informed by the latest food science and policy," said Leslie Dach, executive vice president of corporate affairs at Walmart.

Sandon said that many grocers had been using their own rating system to help shoppers choose healthier options.

"Walmart's approach is not new. Many other stores are already doing this. In general, consumers seem to find these rating systems helpful," Sandon said, "at least the consumers who are trying to make healthier choices."

But others said that food chains like Walmart should hire outside agencies -- such as the USDA or the Centers for Disease Control and Prevention -- to rate foods and provide guidelines that can be applied across stores and settings.

Nutrition Experts: FDA Should Release Health Standards

"The food industry, at the end of the day, is in the business to make money by selling food," said Dr. Stephen Cook of Golisano Children's Hospital at the University of Rochester Medical Center. "If a 'healthy' label on their product gets it to be sold more, then they will try that -- even if it is not true."

Nutrition experts also told ABC News that the FDA should move faster on its 2009 plan to develop a nutritional gold standard for products labeled healthy.

"The FDA is responsible for package labels, so it makes sense that they would establish parameters for what goes on the label," said Connie Diekman, director of University Nutrition at Washington University in St. Louis. "In addition, a consistent criteria for measuring 'healthy' would make shopping much easier for consumers."

In a written statement, Walmart said the labeling criteria "have undergone an extensive evaluation process using thousands of grocery items to help ensure that only nutritious items in each grocery category receive the 'Great for You' icon."

Walmart is not putting a restriction on the new labeling system and said other grocers are welcome to use the system.

For a complete list of the detailed system of what gets the label and what doesn't, click here.